You know a spin-off show is good when it inspires talk of a spin-off of its own.

Better Call Saul has impressed so much that some fans claim it is better than Breaking Bad, the show which first brought us its lead character.

However, all good things must come to an end, and questions are being asked about what will happen in the Vince Gilligan TV universe when its five-season run comes to a close (we’ve only had three so far, so we’ve still got a while).

Naturally, Gilligan, the creator of both critically-acclaimed shows, has a big idea of his own.

"If we were to do another spin-off it would be the Kim Wexler show,” Gilligan told the Sydney Morning Herald.

Wexler, played by Rhea Seehorn, has been a mainstay in the show since its first season and is one of the best-developed characters in the show who didn’t also feature in Breaking Bad.

“She can be hilariously funny, she can be absolutely moving. She can do anything, she just has this astounding range,” Gilligan added.

"Personally, as one of the first two fans of Better Call Saul, I want to know more about Kim, I want to see and learn more about her.”

Gilligan also admitted that Better Call Saul has already exceeded the expectations of those involved in its creation.

The original pitch for the spin-off was a comedy with shorter episodes, playing into lead actor Bob Odenkirk’s stand-up comedy beginnings, but it has grown into much more and even Gilligan himself has been impressed by the way the character of Saul has developed

“I don't know how to answer this without sounding insulting to Bob, but I don't think any of us knew he was going to be as good as he is,” Gilligan said.

“We thought he would be funny and interesting to watch, and that we would write to his strengths, most of which we thought would be his comedy chops.

“And then when we started the show he started acting and acting and suddenly we realised, 'My God, this guy can really go dark, and he can go sad, and he can do all the dramatic things we could ever possibly want from him'.”